Training apparatus, training method, storage medium, and training system

ABSTRACT

A training apparatus includes a display that displays a video image including an image of a moving object, a rotation speed acquirer that acquires a rotation speed of a pedal driven by a user, and a control circuit that changes a moving speed of the object in the video image. The control circuit controls the moving speed as follows. The moving speed of the object in the video image is increased at an acceleration α1 (&gt;0). If an increase in the pedal rotation speed occurs after the moving speed of the object is increased, the moving speed of the object is increased at an acceleration α2 (&lt;α1). In a case where an increase in the rotation speed of the pedal occurs after the moving speed of the object is increased at the acceleration α2, the moving speed of the object is further continuously increased at the acceleration α2.

BACKGROUND

1. Technical Field

The present disclosure relates to a technique of controlling a video image for, in training, allowing a user to achieve a high exercise performance.

2. Description of the Related Art

A bicycle ergometer is known as one of training apparatuses for indoor use. To exercise, a user rides an apparatus simulating a bicycle, and drives a pedal. Continuing such an exercise for a long time may cause the user to feel tired of the exercise. To handle this situation, it has been proposed to put a display in front of a user or put a head-mounted display (HMD) on a head of a user, and a video image is played on the display or the HMD such that the user is allowed to exercise while enjoying watching the video image.

Japanese Unexamined Patent Application Publication 2001-17565 discloses a method of controlling a video image in a training system using a bicycle, a DVD player, and a display. The pedal rotation speed of the bicycle installed in a room is detected using a rotation sensor, and the detected rotation speed is transmitted to the DVD player via an infrared remote control, and a scene video image is displayed on the display. The scene video image is scrolled in accordance with user's eye, and the video playback speed is changed depending on the pedal rotation speed.

SUMMARY

In the technique disclosed in Japanese Unexamined Patent Application Publication 2001-17565, the playback speed of the scene video image is synchronized with the pedal rotation speed when a user drives the bicycle. By displaying the scene video image such that its playback speed is changed in response to an increase or a reduction in the pedal rotation speed, it becomes possible for the user to have a feeling and an atmosphere as if the user were in the scene. However, providing a scene video image in the above-described manner is not necessarily sufficient to allow the user to achieve a high exercise performance.

One non-limiting and exemplary embodiment provides a method of controlling a video playback speed in training so as to allow a user to achieve a higher exercise performance.

In one general aspect, the techniques disclosed here feature a training apparatus including a display that displays a video image including an image of a moving object, a rotation speed acquirer that acquires a rotation speed of a pedal driven by a user, a control circuit that changes a moving speed of the object in the video image, wherein the control circuit performs a control process including (a) increasing the moving speed of the object in the video image at a first acceleration, (b) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and (c) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.

According to the present disclosure, when a user drives the pedal while watching the displayed video image, the user unconsciously increases the rotation speed by being affected by an increasing playback speed of the video image (in other words, by being drawn by the increasing playback speed), which makes it possible to allow the user to achieve a high exercise performance.

Furthermore, by employing the first acceleration αnd the second acceleration lower than the first acceleration to increase the video playback speed, it is possible to effectively induce an increase in the rotation speed of the pedal driven by a user without excessively increasing the video playback speed.

Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. The benefits and/or advantages may be individually obtained by the various embodiments and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and/or advantages.

It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a computer-readable storage medium, or any selective combination thereof. The computer-readable storage medium may be a non-transitory storage medium, for example, a CD-ROM (Compact Disc-Read Only Memory) or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph illustrating an example of a change in a playback speed of a video image in an experiment;

FIG. 2 is a graph illustrating an example of a change in a playback speed of a video image in an experiment;

FIG. 3 is a graph illustrating an example of a change in a playback speed of a video image in an experiment;

FIG. 4 is a graph illustrating an example of a change in a pedal rotation speed measured in an experiment;

FIG. 5 is a graph illustrating an example of a change in a pedal rotation speed measured in an experiment;

FIG. 6 is a graph illustrating an example of a change in a pedal rotation speed measured in an experiment;

FIG. 7 is a graph illustrating an example of a method of controlling a playback speed of a video image according to an embodiment;

FIG. 8 is a graph illustrating an example of a modification to the method of controlling the playback speed of the video image according to the embodiment;

FIG. 9 is a graph illustrating an example of a modification to the method of controlling the playback speed of the video image according to the embodiment;

FIG. 10 is a graph illustrating an example of a modification to the method of controlling the playback speed of the video image according to the embodiment;

FIG. 11 is a block diagram illustrating an example of a functional configuration of a training apparatus according to an embodiment;

FIG. 12A is a diagram illustrating an example of a video image displayed on a display;

FIG. 12B is a diagram illustrating an example of a video image displayed on a display;

FIG. 13 is a diagram illustrating moving directions, as seen in a video image, of objects;

FIG. 14 is a flow chart illustrating an example of an operation of a training apparatus according to an embodiment;

FIG. 15 is a flow chart illustrating an example of an operation of a training apparatus according to an embodiment; and

FIG. 16 is a diagram illustrating an example of a configuration of a training system according to an embodiment.

DETAILED DESCRIPTION Underlying Knowledge Forming Basis of the Present Disclosure

The present inventors have been making an investigation on a technology for helping a user to achieve a high exercise performance in riding an apparatus simulating a bicycle (hereinafter such an apparatus will be referred to simply as a bicycle) by displaying a video image taken from a point of view of a person driving a bicycle along a road.

In the investigation, the present inventors have paid attention to a possibility that the pedal rotation speed is affected by the video playback speed. Via many intensively performed experiments, the present inventors have got an idea on a method of displaying a video image so as to cause a user to unconsciously increase the pedal rotation speed. Note that the term “pedal rotation speed” is used to describe a cadence (the rotation speed about a center axis of a crank) obtained when a user rides a bicycle and drives a pedal, and the term “video playback speed” is used to describe a bicycle traveling speed as seen in the displayed video image.

Examples of experiments made by the present inventors are described below.

In the experiments, a test person worn a head-mounted display (HMD) and drove a bicycle at a speed the person felt constant while watching a ten-minute scene video image whose playback speed was changed in three different patterns A, B, and C. The video image was played twice for each pattern, and the pedal rotation speed was measured when the video image was played back. The first measurement was performed in a situation in which the test person was in a normal state, and the second measurement was performed in a situation in which the test person was tired.

FIG. 1 is a graph illustrating a change in the video playback speed according to the pattern A. In a first half period with a length of 5 minutes (hereinafter referred to as a first 5 minute period), the video playback speed was gradually increased from a normal speed (hereinafter referred to as a 1× speed) to a speed 2 times greater than the normal speed (hereinafter referred to as a 2× speed). In a second half period with a length of 5 minutes (hereinafter referred to as a second 5 minute period), the video playback speed was maintained at the 2× speed.

FIG. 2 is a graph illustrating the change in the video playback speed according to the pattern B. In the first 5 minute period, the video playback speed was gradually increased from the 1× speed to the 2× speed. In the second 5 minute period, the video playback speed was gradually reduced from the 2× speed to a speed one-half the normal speed (hereinafter referred to as a 0.5× speed).

FIG. 3 is a graph illustrating the change in the video playback speed according to the pattern C. In the first 5 minute period, the video playback speed was gradually reduced from the 1× speed to the 0.5× speed. In the second 5 minute period, the video playback speed was gradually increased from the 0.5× speed to the 2× speed.

FIG. 4 is a graph illustrating a pedal rotation speed measured during a full period in which the video image was played according to the pattern A. In the first 5 minute period, the pedal rotation speed gradually increased probably by be affected by the increasing video playback speed. In the second 5 minute period, a further gradual increase in the pedal rotation speed was observed although the video playback speed was maintained constant.

The result suggests that by gradually increasing the video playback speed and then maintaining the video playback speed constant after the pedal rotation speed is increased be being affected by the increasing video playback speed, it is possible to effectively cause the pedal rotation speed to increase without excessively increasing the video playback speed.

FIG. 5 is a graph illustrating a pedal rotation speed measured during a full period in which the video image was played according to the pattern B. In the first 5 minute period, the pedal rotation speed gradually increased as with the pattern A. In the second 5 minute period, the pedal rotation speed gradually decreased after an occurrence of an increase for a short period. Note that the pedal rotation speed at the end of the full period was higher than the initial pedal rotation speed at the beginning of the full period although the video playback speed (0.5× speed) at the end of the full period is lower than the initial video playback speed (1× speed) at the beginning of the full period.

FIG. 6 is a graph illustrating a pedal rotation speed measured during a full period in which the video image was played according to the pattern C. In the first 5 minute period, the pedal rotation speed gradually decreased. In the second 5 minute period, the pedal rotation speed gradually increased after an occurrence of a reduction for a short period. In contrast to the first 5 minute period in which the pedal rotation speed gradually decreased, an abrupt increase in the pedal rotation speed was observed.

These results indicate that the degree to which the rotation speed of the pedal driven by a user decreases by being affected by a reduction in the video playback speed is less than the degree to which the rotation speed of the pedal driven by the user increases by being affected by an increase in the video playback speed. Therefore, reducing the video playback speed after increasing the playback speed is an effective way to prevent a large reduction in the pedal rotation speed and an excessive increase in the playback speed.

Based on the knowledge obtained via the experiments described above, the inventors of the present application have got an idea on a training apparatus, a training method, a program, and a training system for allowing a user to achieve a higher exercise performance.

In an aspect, the present disclosure provides a training apparatus including a display that displays a video image including an image of a moving object, a rotation speed acquirer that acquires a rotation speed of a pedal driven by a user and, a control circuit that changes a moving speed of the object in the video image, wherein the control circuit performs a control process including (a) increasing the moving speed of the object in the video image at a first acceleration, (b) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and (c) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.

According to this aspect, when a user drives the pedal of the bicycle while watching the video image displayed under the control of the training apparatus, the user increases the rotation speed of the pedal unconsciously in response to the video image played back at an increasing playback speed, which makes it possible to allow the user to achieve a high exercise performance.

By reducing the moving acceleration of the object in the video image from the first acceleration to the second acceleration, it is possible to reduce the excessive increase in the moving speed of the object. This makes it possible to prevent a user from having a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and reducing the speed of riding a bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

The control process performed by the control circuit may further include (d) in a case where the change in the pedal rotation speed gets to be within a fixed range after the moving speed of the object in the video image has been continuously increased at the second acceleration, reducing the moving speed of the object in the video image at a third acceleration.

In this aspect, the video playback speed is reduced at the third acceleration. This control is based on the degree to which the rotation speed of the pedal driven by a user is changed by being affected by a decreasing video playback speed is smaller than the degree to which the rotation speed of the pedal driven by the user is changed by being affected by an increasing video playback speed, and this control is effective to prevent an excessive increase in the video playback speed without causing the user to greatly reduce the speed of riding the pedal.

The control process performed by the control circuit may further include (e) in a case where the acquired pedal rotation speed starts to decrease from a fixed range after the moving speed of the object in the video image is increased at a fourth acceleration or reduced at a third acceleration after a predetermined period of time has elapsed since the start of reducing the moving speed of the object in the video image at the third acceleration, increasing the moving speed of the object in the video image at the fourth acceleration.

According to this aspect, by reducing the video playback speed once and then again increasing the video playback speed, it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

According to another aspect, the fourth acceleration may be equal to the first acceleration, and the control process performed by the control circuit may further include (f) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the fourth acceleration, increasing the moving speed of the object in the video image at a fifth acceleration greater than the fourth acceleration.

In this aspect, when the rotation speed of the pedal driven by a user does not increase when the video playback speed is reduced once and then increased again, the video playback speed is increased at a higher acceleration so as to cause the user to unconsciously increase the pedal rotation speed.

The fourth acceleration may be larger than the first acceleration.

In this aspect, by reducing the video playback speed once and then again increasing the video playback speed at the fourth acceleration higher than the first acceleration, it is possible to surely achieve the effect of causing the user to unconsciously increase the pedal rotation speed.

In another aspect, the control process performed by the control circuit may further include (g) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the first acceleration, reducing the moving speed of the object in the video image at a third acceleration.

According to this aspect, in a case where the pedal rotation speed does not change in response to the increase in the video playback speed, the video playback speed is reduced once. This makes it possible to prevent a problem that a user may have a feeling of strangeness of uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

In another aspect, the control process performed by the control circuit may further include (h) in a case where the acquired pedal rotation speed starts to decrease from a fixed range after the moving speed of the object in the video image is increased at a fourth acceleration or reduced at a third acceleration after a predetermined period of time has elapsed since the start of reducing the moving speed of the object in the video image at the third acceleration, increasing the moving speed of the object in the video image at the fourth acceleration.

In this aspect, depending on whether a predetermined period of time has elapsed or a reduction in the pedal rotation speed occurs after the video playback speed is reduced once, the video playback speed is started to be increased again.

In an aspect, the present disclosure provides a training method, including acquiring a rotation speed of a pedal driven by a user, increasing a moving speed of an object in a video image displayed on a display at a first acceleration, in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.

In this aspect, when a user drives the pedal of the bicycle while watching the video image displayed according to the training method, the user increases the rotation speed of the pedal unconsciously in response to the video image played back at an increasing playback speed, which makes it possible to allow the user to achieve a high exercise performance.

By reducing the moving acceleration of the object in the video image from the first acceleration to the second acceleration, it is possible to reduce the excessive increase in the moving speed of the object. This makes it possible to prevent a problem that a user may have a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

In an aspect, the present disclosure provides a program that causes a computer to execute a process including acquiring a rotation speed of a pedal driven by a user, increasing a moving speed of an object in a video image displayed on a display at a first acceleration, in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.

According to this program, when a user drives the pedal of the bicycle while watching the video image displayed under the control of the computer executing the program, the user increases the rotation speed of the pedal unconsciously in response to the video image played back at an increasing playback speed, which makes it possible to allow the user to achieve a high exercise performance.

By reducing the moving acceleration of the object in the video image from the first acceleration to the second acceleration, it is possible to reduce the excessive increase in the moving speed of the object. This makes it possible to prevent a problem that a user may have a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

In an aspect of the present disclosure, a training system includes a display that displays a video image including an image of a moving object, a bicycle that detects a rotation speed of a pedal driven by a user, and a control apparatus that changes a moving speed of the object in the video image, wherein the control apparatus performs a process including (a) increasing the moving speed of the object in the video image at a first acceleration, (b) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and (c) in a case where an increase in the detected rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.

In this aspect, as with the training apparatus described above, it is possible to realize a training system capable of allowing a user to achieve a high exercise performance.

It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a computer-readable storage medium such as a CD-ROM, or any selective combination thereof.

A training apparatus, a training method, a program, and a training system according to an embodiment of the present disclosure are described in detail below with reference to drawings.

Note that each embodiment described below is for illustrating a specific example of the present disclosure. That is, in the following embodiments of the present disclosure, values, shapes, materials, constituent elements, locations of the constituent elements and manners of connecting the constituent elements, steps, the order of steps, and the like are described by way of example but not limitation. Among constituent elements described in the following embodiments, those constituent elements that are not described in independent claims indicating highest-level concepts of the present disclosure are optional.

Training Method

Based on the knowledge obtained via the experiments, the present inventors have got an idea on a method of controlling a video playback speed such that a user can achieve a higher exercise performance when the user drives a bicycle while watching a video image. This method of controlling the video playback speed is an example of a training method according to the present disclosure.

FIG. 7 is a graph illustrating an example of a method of controlling the video playback speed according to an embodiment. In the example shown in FIG. 7, the video playback speed is gradually increased (in period from t0 to t1) at an acceleration α1 (>0). After the pedal rotation speed is increased under influence of the video image, the video playback speed is maintained (in a period from t1 to t2) at an acceleration α2 (=0).

According to the knowledge obtained via the experiments, even when the video playback speed is maintained constant in the above-described manner, the pedal rotation speed is further increased for a certain period. This makes it unnecessary to further increase the video playback speed until the playback speed may reach an excessively high value. This makes it possible to prevent a problem that a user may have a feeling of a strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. That is, it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

At a certain point of time (in a period from t2 to t3) after the video playback speed is made constant, the pedal rotation speed starts to approach a saturated value. In this case, the video playback speed is reduced at an acceleration α3 (<0) (in a period from t3 to t4), and then the video playback speed is gradually increased at an acceleration α4 (>0) (in a period from t4). The acceleration α4 may be equal to the acceleration α1 or greater than the acceleration α1.

According to the knowledge obtained via the experiments, the degree to which the rotation speed of the pedal driven by a user is changed by being affected by a decreasing video playback speed is less than the degree to which the rotation speed of the pedal is changed by being affected by an increasing video playback speed. This means that the pedal rotation speed tends not to easily decrease when the video playback speed is reduced. Increasing the video playback speed again after slightly reducing the video playback speed makes it possible to prevent an excessive increase in the video playback speed. This makes it possible to prevent a problem that a user may have a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. That is, it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

FIG. 8 is a graph illustrating an example of a modification to the method of controlling the video playback speed according to the embodiment. As illustrated in FIG. 8, in the period from t1 to t2, the video playback speed may be gradually increased at an acceleration α2 lower than the acceleration α1 employed in the period from t0 to t1.

FIG. 9 is a graph illustrating an example of a modification to the method of controlling the video playback speed according to the embodiment. The example shown in FIG. 9 illustrates a manner of controlling the video playback speed in a case where the pedal rotation speed is not changed by being affected by a video image when the video playback speed is increased (in a period from t0 to t1). For a similar reason to that described above, after the video playback speed is reduced at an acceleration α3 (<0) (in a period from t1 to t2), the video playback speed is gradually increased at an acceleration α4 (>0) (in a period from t2). Because the pedal rotation speed does not change by being affected by the video image when the video playback speed is increased at an acceleration α1 in a period from t0 to t1, the video playback speed in the period from t3 may be increased at an acceleration α4 greater than the acceleration α1 employed in the period from t0 to t1.

FIG. 10 is a graph illustrating an example of a modification to the method of controlling the video playback speed according to the embodiment. The example shown in FIG. 10 illustrates a manner of controlling the video playback speed in a case where an increase in the pedal rotation speed does not occur when the video playback speed is maintained at a constant value (in a period from t1 to t2). For a similar reason to that described above, after the video playback speed is reduced at an acceleration α3 (<0) (in a period from t2 to t3), the video playback speed is gradually increased at an acceleration α4 (>0) (in a period from t3).

Configuration of Training Apparatus

A description is given below as to a training apparatus that executes the training method described above.

FIG. 11 is a block diagram illustrating an example of a functional configuration of the training apparatus according to the present embodiment. The training apparatus 100 includes a display 1, a rotation speed acquirer 2, and a control circuit 3. The control circuit 3 includes a video accelerator 31, a determiner 32, a video acceleration changer 33, and a video decelerator 34.

Display 1

The display 1 displays a video image when a user is driving a pedal of a bicycle. The display 1 may be realized using, for example, a flat panel display disposed in front of the bicycle or in a vicinity of the bicycle, or an HMD worn by a user on his/her head. The video image displayed on the display 1 is controlled by the control circuit 3.

FIG. 12A and FIG. 12B are diagrams each illustrating a non-limiting example of a video image displayed on a display. As illustrated by way of example in FIG. 12A and FIG. 12B, the video image displayed on the display 1 may be a perspective video image of a scene taken from a point of view (hereinafter referred to as a virtual point of view) of a person riding a bicycle on a road. FIG. 12B illustrates a video image that is displayed when the virtual point of view moves a particular distance after the video image shown in FIG. 12A is displayed.

In FIG. 12A and FIG. 12B, reference numerals 121 and 122 denote two objects existing in a scene represented in each video image. The objects 121 and 122 each may be any object such as a car, a person, a road sign, a tree, and the like.

The positions in the video image where the objects 121 and 122 are displayed move in directions radially expanding from a center point 130 as represented by arrows 131 and 132.

The moving directions of the positions of the displayed objects 121 and 122 each have a vertical component as seen on a display screen of the display 1. That is, the positions where the objects 121 and 122 are displayed move at least in the vertical direction.

In a case where the video image includes a plurality of objects (such as objects 121 and 122 in the present example), the moving direction of the object 121 represented by the arrow 131 and the moving direction of the object 122 represented by the arrow 132 have horizontal components that may be opposite about the center point 130.

When a user is looking at the center point 130, movement of the objects 121 and 122 causes the user to feel as if the user himself/herself moves. Note that the center point 130 does not necessarily need to be located in the center of the display screen surface of the display 1. For example, in a case where the video image simulates a situation in which a user looks ahead in the moving direction, the center point 130 may be located in the center of the video image. In a case where the video image simulates a situation in which a user looks in a direction (for example, in a sideward direction) other than the moving direction, the center point 130 may be located at a position different from the center of the video image. The center point 130 may be an intersection between the arrow 131 and the arrow 132.

FIG. 13 is a diagram illustrating an example of a moving direction and a moving speed of an object in a video image in which the moving direction is represented by the direction of an arrow and the moving speed is represented by the length of the arrow. In this specific example, the objects are such objects that do not move in an actual world. However, in the video image, the objects move in directions including directions expanding radially from the center point 130. Moving speeds as seen in the video image are small for objects at distant locations and large for objects closer to the virtual point of view.

In a case where the video image includes a moving object that moves in the actual world, the movement thereof in the actual world results in a complicated movement as seen in the video image. For example, in a case where the moving object is a car whose speed is higher than the speed of the bicycle, the size of the car in the video image may decrease as the car moves away toward the center point 130.

Note that in the present description, the term “moving speed of objects in the video image” is used to represent the average moving speed of objects displayed in the video image, and more specifically, the moving speed is the video playback speed.

Rotation Speed Acquirer 2

The rotation speed acquirer 2 acquires the rotation speed of the pedal when a user drives the bicycle. More specifically, the rotation speed acquirer 2 may be configured using a receiver that receives the rotation speed of the pedal, wirelessly or via a cable, from the rotation speed sensor disposed on the bicycle.

Control Circuit 3

The control circuit 3 controls the video image displayed on the display 1. More specifically, the control circuit 3 displays the video image on the display 1 at a controlled video playback speed. The control circuit 3 may be realized, for example, using a microprocessor or a dedicated hardware circuit, or a combination thereof. The rotation speed acquirer 2 may be included in the control circuit 3.

Video Accelerator 31

The video accelerator 31 increases the moving speed of the object in the video image (that is, the video accelerator 31 increases the video playback speed of the video image).

Determiner 32

The determiner 32 determines a condition in terms of the rotation speed of the pedal and determines a method of controlling a next video image according to the condition. The condition is, for example, whether the rotation speed of the pedal changes in response to an increase in the video playback speed of the video image (in other words, whether the increase in the video playback speed results in an increase in the pedal rotation speed), whether the pedal rotation speed is maintained at an increased value, or whether the pedal rotation speed starts to decrease.

Video Acceleration Changer 33

The video acceleration changer 33 changes the acceleration of the moving speed of objects in the video image (that is, the acceleration of the video playback speed of the video image).

Video Decelerator 34

The video decelerator 34 reduces the moving speed of the objects in the video image (that is, the video playback speed).

Operation of Training Apparatus

Next, an operation of the training apparatus 100 configured in the above-described manner is described below.

FIG. 14 is a flow chart illustrating an example of an operation of the training apparatus 100. The training apparatus operates as follows according to the flow chart illustrated in FIG. 14.

The video accelerator 31 gradually increases the video playback speed. Herein, it is assumed by way of example that the playback acceleration is first acceleration α1 greater than 0 (S101).

The rotation speed acquirer 2 acquires a pedal rotation speed (S102).

The determiner 32 determines whether the pedal rotation speed changes in response to an increase in the video playback speed (S103). In this case, the change in the pedal rotation speed is an increase in the pedal rotation speed. In a case where a change in the pedal rotation speed occurs (Yes in step S103), the processing flow proceeds to step S104, but otherwise (No in S103), the processing flow proceeds to step S108. In a case where the pedal rotation speed changes in response to an increase in the video playback speed, the rotation speed increases after the video playback speed is increased. Note that the term “after the video playback speed is increases” is used to describe both a period over which the video playback speed is being increased and a period after the video playback speed has been increased. For example, in the case shown in FIG. 7, the period denoted by “after the video playback speed is increased” includes a period from t0 (exclusive) to t1 and a period from t1 to t2.

The video acceleration changer 33 reduces the playback acceleration to a second acceleration α2 (S104). The second acceleration α2 is equal to or greater than 0 and smaller than the first acceleration α1. In a case where the second acceleration α2 is equal to 0, the video playback speed is maintained at a constant value. Note that the constant value is a video playback speed as of when the playback acceleration becomes 0.

The rotation speed acquirer 2 acquires a pedal rotation speed (S105).

The determiner 32 determines whether the rotation speed is still continuously increasing (S106). In a case where the rotation speed is still continuously increasing (Yes in S106), the processing flow proceeds to step S107. In a case where the rotation speed is not increasing (No in S106), the processing flow proceeds to step S108. The determination as to whether the rotation speed is still continuously increasing is performed, for example, by determining whether the pedal rotation speed is equal to or greater than a predetermined threshold value greater than 0.

The video accelerator 31 maintains the second acceleration α2 determined in step S104 (S107).

The video decelerator 34 gradually reduces the video playback speed (S108). In this step, a third acceleration α3 smaller than 0 is employed as the playback acceleration.

When a predetermined period of time has elapsed since the start of reducing the video playback speed at the third acceleration α3 (Yes in S109), the video accelerator 31 gradually increases the video playback speed (S112). In this step, a fourth acceleration α4 larger than 0 is employed as the playback acceleration. The fourth acceleration α4 may be larger than the first acceleration α1. Alternatively, first, the fourth acceleration α4 may be set to be equal to the first acceleration α1, and, if no increase in the rotation speed occurs, the playback acceleration may be increased to a fifth acceleration α5 greater than the fourth acceleration α4.

FIG. 15 is a flow chart illustrating another example of an operation of the training apparatus 100. In this example, the training apparatus operates as follows according to the flow chart illustrated in FIG. 15.

In steps S101 to S108, the training apparatus 100 operates in a similar manner as described above with reference to FIG. 14.

Thereafter, the rotation speed acquirer 2 acquires a pedal rotation speed (S110).

The determiner 32 determines whether the pedal rotation speed starts to decrease from a fixed range (S111). In a case where it is determined that the pedal rotation speed starts to decrease from the fixed range (Yes in step S111), the processing flow proceeds to step S112, but otherwise (No in step S111) the processing flow proceeds to step S108.

The video accelerator 31 gradually increases the video playback speed (S112). In this step, a fourth acceleration α4 larger than 0 is employed as the playback acceleration. The fourth acceleration α4 may be larger than the first acceleration α1. Alternatively, first, the fourth acceleration α4 may be set to be equal to the first acceleration α1, and, if no increase in the rotation speed occurs, the playback acceleration may be increased to a fifth acceleration α5 greater than the first acceleration α1.

Thus the training apparatus 100 allows a user to drive the pedal while watching the video image displayed on the display 1 under the control of the control circuit 3, which may cause the user to increase the rotation speed of the pedal unconsciously in response to an increase in the playback speed of the video image displayed. Thus it is possible to allow the user to achieve a high exercise performance.

The training apparatus 100 is capable of preventing an excessive increase in the video playback speed by increasing the video playback speed at the acceleration α1 and the second acceleration α2 lower than the first acceleration α1. This makes it possible to prevent a problem that a user may have a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

In the training apparatus 100, the video playback speed is reduced at the third acceleration α3 and then the video playback speed is gradually increased at the fourth acceleration α4. According to the knowledge obtained via the experiments, the degree to which the rotation speed of the pedal driven by a user is changed by being affected by a decreasing video playback speed is less than the degree to which the rotation speed of the pedal is changed by being affected by an increasing video playback speed. Therefore, this control is effective to prevent an excessive increase in the video playback speed without causing the user to greatly reduce the speed of riding the pedal. This makes it possible to prevent a problem that a user may have a feeling of strangeness or uneasiness on a video image played back at too fast a playback speed and the user may reduce the speed of driving the bicycle. Thus it is possible to effectively allow a user to achieve a high exercise performance within a range of the playback speed that does not cause the user to have a feeling of strangeness.

Training System

FIG. 16 is a diagram illustrating an example of a configuration of a training system according to the present embodiment. The training system 300 includes the training apparatus 100, and a bicycle 200. The training apparatus 100 includes, as described above, the display 1, the rotation speed acquirer 2, and the control circuit 3. The bicycle 200 includes a not-illustrated rotation speed sensor that detects a rotation speed of a pedal.

The display 1 may be realized using an HMD worn by a user. The rotation speed acquirer 2 may be realized using a receiver that receives a result of a detection of the rotation speed of the pedal from the rotation speed sensor of the bicycle 200. The control circuit 3 may be realized using a personal computer. Transmission of data from the rotation speed acquirer 2 to the control circuit 3 and transmission of data from the control circuit 3 to the display 1 may be performed wirelessly or via a cable.

The training apparatus according to the present disclosure may be used as a health appliance, fitness equipment, or the like. 

What is claimed is:
 1. A training apparatus comprising: a display that displays a video image including an image of a moving object; a rotation speed acquirer that acquires a rotation speed of a pedal driven by a user; and a control circuit that changes a moving speed of the object in the video image, wherein the control circuit performs a control process including (a) increasing the moving speed of the object in the video image at a first acceleration, (b) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and (c) in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.
 2. The training apparatus according to claim 1, wherein the control process performed by the control circuit further includes (d) in a case where the change in the pedal rotation speed gets to be within a fixed range after the moving speed of the object in the video image has been continuously increased at the second acceleration, reducing the moving speed of the object in the video image at a third acceleration.
 3. The training apparatus according to claim 2, wherein the control process performed by the control circuit further includes (e) in a case where the acquired pedal rotation speed starts to decrease from a fixed range after the moving speed of the object in the video image is increased at a fourth acceleration or reduced at a third acceleration after a predetermined period of time has elapsed since the start of reducing the moving speed of the object in the video image at the third acceleration, increasing the moving speed of the object in the video image at the fourth acceleration.
 4. The training apparatus according to claim 3, wherein the fourth acceleration is equal to the first acceleration, and the control process performed by the control circuit further includes (f) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the fourth acceleration, increasing the moving speed of the object in the video image at a fifth acceleration greater than the fourth acceleration.
 5. The training apparatus according to claim 3, wherein the fourth acceleration is greater than the first acceleration.
 6. The training apparatus according to claim 1, wherein the control process performed by the control circuit further includes (g) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the first acceleration, reducing the moving speed of the object in the video image at a third acceleration.
 7. The training apparatus according to claim 6, the control process performed by the control circuit further includes (h) in a case where the acquired pedal rotation speed starts to decrease from a fixed range after the moving speed of the object in the video image is increased at a fourth acceleration or reduced at a third acceleration after a predetermined period of time has elapsed since the start of reducing the moving speed of the object in the video image at the third acceleration, increasing the moving speed of the object in the video image at the fourth acceleration.
 8. The training apparatus according to claim 7, wherein the fourth acceleration is greater than the first acceleration.
 9. The training apparatus according to claim 1, wherein the control process performed by the control circuit further includes (i) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the second acceleration, reducing the moving speed of the object in the video image at a third acceleration.
 10. The training apparatus according to claim 9, wherein the control process performed by the control circuit further includes (j) in a case where the acquired pedal rotation speed starts to decrease from a fixed range after the moving speed of the object in the video image is increased at a fourth acceleration or reduced at a third acceleration after a predetermined period of time has elapsed since the start of reducing the moving speed of the object in the video image at the third acceleration, increasing the moving speed of the object in the video image at the fourth acceleration.
 11. The training apparatus according to claim 10, wherein the fourth acceleration is equal to the first acceleration, and the control process performed by the control circuit further includes (k) in a case where an increase in the acquired rotation speed of the pedal does not occur after the moving speed of the object in the video image is increased at the fourth acceleration, increasing the moving speed of the object in the video image at a fifth acceleration greater than the fourth acceleration.
 12. The training apparatus according to claim 10, wherein the fourth acceleration is greater than the first acceleration.
 13. A training method comprising: acquiring a rotation speed of a pedal driven by a user; increasing a moving speed of an object in a video image displayed on a display at a first acceleration; in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration; and in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.
 14. A storage medium including a control program for causing a device including a processor to execute a process, the storage medium being non-transitory and readable by a computer, the process comprising: acquiring a rotation speed of a pedal driven by a user; increasing a moving speed of an object in a video image displayed on a display at a first acceleration; in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration; and in a case where an increase in the acquired rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.
 15. A training system comprising: a display that displays a video image including an image of a moving object; a bicycle that detects a rotation speed of a pedal driven by a user; and a control apparatus that changes a moving speed of the object in the video image, wherein the control apparatus performs a process including (a) increasing the moving speed of the object in the video image at a first acceleration, (b) in a case where an increase in the detected rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the first acceleration, increasing the moving speed of the object in the video image at a second acceleration that is equal to or greater than 0 and is smaller than the first acceleration, and (c) in a case where an increase in the detected rotation speed of the pedal occurs after the moving speed of the object in the video image is increased at the second acceleration, further continuously increasing the moving speed of the object in the video image at the second acceleration.
 16. An apparatus, comprising: a controller that causes a display to display first images during a first period, second images during a second period immediately after the first period, third images during a third period immediately after the second period, and fourth images during a fourth period immediately after the third period, the first images, the second images, third images, and fourth images being presented to a user; and a rotation speed acquirer that receives, from a sensor attached to a pedal driven by the user, first rotation speeds of the pedal during the first period, second rotation speeds of the pedal during the second period, third rotation speeds of the pedal during the third period, and fourth rotation speeds of the pedal during the fourth period, wherein the controller causes the display (i) to display the first images at a positive acceleration when the controller detests the first rotation speeds increasing, (ii) to display the second images at a constant speed when the controller detects the second rotation speeds increasing, (iii) to display the third images at the constant speed when the controller detects the third rotation speeds not increasing, and (iv) to display the fourth images at a negative acceleration when the controller detects the fourth rotation speeds not increasing. 